No idea why you´re setting the flags in GIFR, but that should not matter much.
What is the INT2 in the if(INT2) in the isr? Try leaving just the LD_BUZZER_LED_ON without the condition and see what happens.
Also since you have int1 and int0 enabled, make sure you have the corresponding isrs in the code, or else the mcu will reset if the pin triggers.

No idea why you´re setting the flags in GIFR, but that should not matter much.
What is the INT2 in the if(INT2) in the isr? Try leaving just the LD_BUZZER_LED_ON without the condition and see what happens.
Also since you have int1 and int0 enabled, make sure you have the corresponding isrs in the code, or else the mcu will reset if the pin triggers.